Well servicing rig



May 4, 1965 E. A. BENDER 3,181,653

' WELL SERVICING RIG Filed June 15, 1959 4 Sheets-Sheet 1 ZZZ" //d ATTORNEYS May 4, 1965 E. A. BENDER WELL SERVICING RIG 4 Sheets-Sheet 2 Filed June 15, 1959 y 4, 1965 E. A. BENDER 3,181,658

' WELL SERVICING RIG Filed June 15, 1959 4 Sheets-Sheet 3 ,5 INVENTOR 2372124 Jame);

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WELL SERVICING RIG Filed June 15, 1959 4 Sheets-Sheet 4 ZZZ/1.36m); w

ATTORNEYS United States Patent 3,181,658 WELL SERVICING RIG Emil A. Bender, P.0. Box 52, Bakersfield, alif. Filed June 15, 1959, Ser. No. 820,330 Qlaims. (Cl. 1891l) The present invention relates generally to oil derricks and is more particularly directed to certain new and useful improvements in portable rigs or masts of the type especially adapted for use in the servicing of drilled wells of any type.

In the drilling of oil and gas wells by the so-called rotary method, it is customary to employ relatively large and heavy derricks in order to withstand the extremely high loads which are frequently encountered during the drilling operation. However, when the drilling operation is finished and the well completed, the drilling derrick is normally moved from the well site for use in another drilling operation. Thus, when a completed well requires servicing for any of a variety of reasons, it is necessary to bring in a new derrick or rig of some sort to run tubing or to handle any of the many different tools which may be required to correct the particular difliculty.

Where a well ring is intended principally for the servicing of existing wells, it is not necessary that the mast or other equipment be as heavy as the drilling rigs mentioned above. On the other hand, it is still desirable to provide 7 servicing masts of suflicient height to run what are commonly referred to as doubles or two standard tubing lengths connected together, so that the servicing operation can be completed quickly. In adjusting to these requirements, the art has turned to portable truck-mounted rigs which may be transported quickly and inexpensively to the well site and removed therefrom with equal facility.

As is well known to those skilled in the art, the mounting'of a well servicing mast upon a truck body as heretofore proposed creates many problems despite the ger1- erally lighter weight and bulk of such equipment. One

such problem arises from the laws or ordinances of the different states which, of necessity, must place some limits upon the overall size and weight of equipment which may be driven over the public highways. At the present time, most of the states permit an overhang from the rear of a truck of approximately two-thirds the length of the truck wheelbase but not to exceed a fixed distance from the rear of the truck chassis or rear tire. In the case of front overhang, the requirements are generally even stricter, being limited to not more than three feet from the front bumper and the bumper inturn being limited to not more than twelve or eighteen inches from the front tire. Since the entire truck length can not be over thirty-five to forty feet nor carry loads in excess of eighteen thousand pounds per single axle, it is apparent that both weight and overhang in the case of a truckmounted mast become critical where it is desired to have the mast sutficiently high to handle two sections of tubing at a time.

In the light of the foregoing, it is an important object of the present invention to provide a truck-mounted Well servicing rig of the type described wherein the mast is of sufficient height to handle double lengths of tubing and yet the entire assembly is completely roadable in compliance with law.

A principal object of the invention is to provide a rig of the type described wherein the mast is pivoted about a movable hinge so that the lifting leg may operate to raise the mast with maximum efficiency.

Another object of the invention is to provide a rig of the type described wherein the mast may be erected in a a continuous operation which first causes the hinge support to pivot about the truck body to raise the hinge point and ice thereafter causes the lifting leg to raise the mast into operating position.

A further object of the invention is to provide a mast of the type described having upper and lower sections pivotally connected together in such manner that the upper section may be moved between a depending road transport position relative to the lower section and an operating position in which it forms a continuation of the lower section.

Another object of the invention is to provide a rig of the type described embodying a mast of generally triangular cross-section having a single rear leg so that a single lifting leg may be employed in raising the mast.

A still further object of the invention is to provide a novel method of raising a mast of the type described wherein the main mast hinge is first elevated above the base and thereafter a lifting leg is employed to raise the mast about its pivot.

An additional object of the invention is to provide a rig of the type described which is of extremely simple and rugged construction and which will require a mini mum of maintenance attention in normal use.

The foregoing together with other and further objects and advantages of the invention will become more readily apparent to those skilled in the art from a consideration of the following detailed specification taken in conjunction with the accompanying figures of drawing in which:

FIGURE 1 is a generally schematic side elevational view of a truck-mounted well servicing rig in accordance with the present invention, the mast being shown in raised or normal operating position;

FIGURE 2 is a side elevational view of the rig of FIGURE 1 but showing the same in full lines in road transport position;

FIGURE 3 is a side elevational view of the rig of FIG- URES 1 and 2 but illustrating the mast and hinge support in an intermediate position which the parts will occupy during a mast raising or lowering operation;

FIGURE 4 is a front elevational view of the rig illustrated in FIGURES 1, 2 and 3, bearing in mind that the front of the rig, like the front of the mast, faces to the rear of the truck;

FIGURE 5 is a fragmentary transverse cross-sectional view taken substantially along the line 55 of FIGURE 4;

FIGURE 6 is a fragmentary transverse cross-sectional view taken substantially along the line 6-45 of FIGURE 4;

FIGURE 7 is a top plan view of the crown block assembly of the mast shown in FIGURE 1 but to a slightly enlarged scale;

FIGURE 8 is a fragmentary detail view illustrating portions of the upper and lower mast sections to show a preferred manner in which they may be pivotally connected together;

FIGURE 9 is a fragmentary detail view similar to FIGURE 8 but illustrating the mast sections pivoted into road transport position; and

FIGURE 10 is a detail cross-sectional view illustrating schematically a typical automatic latch which may be employed to lock the upper mast section in extended position, taken substantially along the line 10-10 of FIGURE 8.

Referring now in somewhat greater detail to the various figures of the drawings, and in particular to FIGURE 1 thereof, the improved well servicing rig in accordance with the present invention is shown as being mounted upon a conventional truck designated generally by reference numeral 2th and having the usual truck body or base 22, cab 24, and wheels 26. The truck body 22 also carries a conventional draw works 28 which is rigidly attached thereto in any convenient manner and suitably braced as by means of braces 30. At its front end, the truck also carries a pedestal support 32 which serves to support the forward or upper portion of the mast designated generally.

by reference numeral 34 when the latter, is in lowered or Asperhaps best'illustrated in FIGURE 6, the mast 34 is of generally triangular cross-section having a pairof front legs 40 and a single rear leg 42' interconnected by horizontal girts 44. a Each of the legs 40-42 is preferably of hollow tubular construction and it will also be noted that I prefer not to employ any diagonalbracing, each ofv the girts 44 being of a special rigid construction including a pair of spaced tubular members welded or otherwise suitably secured to'a central Web. A mast construction of this type has been found to possess the necessary strength and rigidity for normal well servicing operations and, at the same'time, achieves improved visibility for the operator 'both'while the mast is in operating position and -when it is in road transport position as will be hereinafter more fully described. The'mast 34 also preferably comprises upper and lower mast sections designated generally by reference numerals 46 and 48, respectively, which are, pivotally connected together as indicated at 50 for a rea- -son which will also be hereinafter more fully set forth.

The mast 34 is pivotally connected to a pair of main fhinge supports provided at opposite sides of'the truck body or base 22 at opposite sides of the latter and adjacent the rear thereof. includes two members 52 and 54. which are pivotally connected at their outer ends as "indicated by reference numeral"56 and pivotally connected at their inner ends to spaced points 58 and 60 on the truck body or base 22.. It will be noted that the pivots 60 at the lower ends of I the members 52 are slightly offset in order to afford additional space for working around a well whereas the pivots 58 are fixed in suitable pedestal structures inor base 22.

As is, best indicated by a comparison of FIGURES 2 and 3, the members 54 forming parts of the main hinge supports, are capable of limited extensibility, each comprising a pair of telescopically'arranged sections slidable one 'within the other and including limit stops 64 which 'serve to limit the maximum extension of the members.

The mast 34 is pivotally connected to the hinge supports by means of main hinges 66 provided at the lower ends. of

each of the front legs 40. From the construction thus far described, it will be apparent that each of the members 52-54 may pivot about the points 60-58 as the member -54 contracts in length so that the hinge supports as a whole pivot about the truck body or base 22 in such manner'as'toraise or elevate the main hinges 66 above the latter fromithe position shown in FIGURE 2 to the position shown in FIGURES.

The mast 34'is elevated into normal operating position through employment of the so-called lever lift principle in which a lifting leg inslidable contact with the I mast causesthe latter to pivot about its main hinge;and, when the mast is fully elevated, the liftingleg is securely attached to the mast so as tobecome a, rigid part of the mast support. In'the present case, the'lifting leg is designated by reference numeral 68 and as shown. in FIG- URE 6, since the mast 34 includes only a single rear leg 42, the lifting leg 68 is also in the form of a'single A frame pivotally connected at 70 to a fixed cross ba r 72 secured to the support 62. At its outer end, the; lifting leg" or A frame 68 is provided with 'a pair of guides .'74 having a roller 76 mounted Ztherebetween and adapted to slidably engage the rear mast leg 42. This construction;

The pedestal 32 may also con-;

- strain the roller 76 from sidewise movement.

, matic latch is also provided. between the guides 74 so as Each of themain hinge supports 4 a ,7 as shown in FIGURE 6, is such as to permit the roller 76 to slide along the rear mast leg 42 Without substantial friction while at the same time the guides 74 serve to re- An autoto positively'lockthe lifting leg 68 to the mast 34 when the latter .isin fully'elevatedposition as shown in FIG URE 1. This latch may be of any type well known in the art and is, therefore, not described herein in detail and it will be understood that, in accordance with the usual practice, the latch operates automatically to engage the rear leg 42 of the mast 34 when the latter reaches its elevatedjoperating position and may be manually disengaged therefrom prior to commencing a mast lowering operation. p I v As mentioned above, the mast 34 includes upper and lower sections 46 and 48 pivotally connected together in any convenient manner'as by means of the pivots 50 provided in the front legs 40. As shown in FIGURE 2 and, toga slightly enlarged scale, in FIGURES 8 and 9, the pivoting movement of the upper and lower mast sections 4648' is permitted by means of a toggle mechanism interposed in the rear mast leg 42. This toggle mechanism comprises a pair of arms 80 and 82 pivotally connected'together as at 84 and pivotally connected at their opposite ends to the: adjacent ends of the leg 42 as indicated by reference numerals 86 and 88. It will be noted that the arm 80 is appreciably longer than the arm 82 so that the extension 90 of arm 80 can overlap and surround the arm 82 when the parts are in the position as shown in FIGURE 8. At this portion of themast adjacent the pivots 50,- additional bracing structure is preferablyprovide'din the form of diagonal braces 92.

Still referring particularly -to FIGURES. 2, 8, 9 and also to, FIGURE 10, it will be noted'that' the diagonal braces, 92 forming part of the lower mast section 48 carry betweenv them a shaft 94 on which isrotatably mounted a pulley or sheave 96. A line 98 extends over the sheave 9 6 and is securely attached as at 100 to the outer portion of the extension 90 of the arm 80. It'fwill thus be apparent .that, with the parts as shown in 'FIG- dicated by the beams 62 rigidly attachedto the truck body I 1 URE 9, or in full lines in FIGURE 2,'the upper mast section 46 maybe moved to'theldotted line position of FIGURE 2 or tothe position as shown in FIGURE 8 by applying a suitable strain-or tension to the line 98 and, for this purpose, the line 98 may extend over an- 2) to the usual cathead 104 other sheave1102 (FIGURE of the draw. works 28. I I

In order to 'releasably retain the upper mastsection 46 in itsnormal operating position as illustrated in FIG- URE 8, there is providedpa spring pressed latch mechanism 106' which is illustrated schematically in FIGURE 10. ,As shown in this view, the latch 106 comprises a bracket 108 secured v atoneside' of the U-shaped extension 90 and carrying aplunger 110 which projects through suitable apertures provided in the members 82 and 90 and is held in place therein as by means of a spring 112. The plunger. 110 may be" manually retracted by means of a knob 114 for the purpose of releasing the assembly to permit the parts to move from the position illustrated in FIGURE 8 to that shown in FIGURE 9. It is to be understood that the spring loaded latch illustrated scher'natically inFIGURE 10 is intended to be merely typical of many such latching devices known to the art and could equally well take the form of .an electricalor fluid pressure actuated device.

The crown block assembly at the top of the mast 34 is best illustrated in. FIGURE 7 and preferably employs, in a modified form, 'the crossover sheave principles as set forth inmy prior Patent No; 2,440,427. In the present case, the fast and dead linefsheaves 116-118 as well as the crossover sheave l20 are rotatably mounted in depending brackets 122 (FIGURE 4) which hang from a generally triangular box frame 124. The box frame 124 is suitably secured as by welding or the like to the top ends of the front and rear mast legs 40-42. For a more extended discussion of the principles and advantages of a crown block assembly of this type, reference may be had to my aforesaid Letters Patent No. 2,440,427. However, forthe purposes of the present invention, it will be understood that the usual fast and dead lines are provided as indicated at 126 in FIGURE 1 and are connected in the usual endless stringup between the main drum of the draw works 28 and the usual travelling block indicated schematically in FIGURE 1 and designated by reference numeral 128.

In FIGURE 1 wherein the rig is illustrated in normal operating position, there is also shown a racking platform 130 which is pivotally connected to the front legs 40 of the mast 34 by means of offset brackets 132. The racking platform 130 may be held in place in any convenient manner as by means of the inclined braces 134, and, as indicated in FIGURE 2, the offset brackets 132 provide a working space for the travelling block 128. A stand of pipe in the form of doubles is designated generally by reference numeral 136 and extends in the usual manner between the racking platform 130 and a suitable support 138 at the ground level. As mentioned above, and as Will be clearly appreciated by those skilled in the art, the showing throughout the various figures of the drawings is, of necessity, largely schematic in view of the tremendously reduced scale required. For this reason, only so much of the detail as is deemed necessary to an understanding of the invention has been set forth.

Under operating conditions, the working loads upon the rear leg 42 of the mast are transmitted in part through the lifting leg 68 and vertical brace 62 to the vehicle body 22 and suitable jacks 61 are employed to transmit these loads to the ground. However, the working loads upon the front legs 40 of the mast are not transmitted to the vehicle body but, instead, are carried through the hinges 66 to a pair of outrigger braces designated generally by reference numeral 140 which are pi-votally connected by mean-s of double hinge brackets 142 to the lower ends of the front mast legs 49 adjacent the main hinges 66. The lower ends of the outrigger braces 140 are supported by generally horizontal braces 144 pivotally connected at their inner ends as indicated at 145 to the extreme rear of the vehicle body 22 and another generally horizontal pair of braces 147 connected as indicated by numeral 149 to the sides of the vehicle frame 22. As shown in FIGURE 5, the braces 147 are adjustable in length by means of removable pins 151 which may be engaged within appropriate holes 153 provided in the telescopic brace extensions 155. When not in use, the extensions 155 are retracted, disconnected from the outrigger braces 141), and swung inwardly along the sides of the vehicle body or frame 22. The horizontal braces 144- may likewise be disconnected from the lower ends of the outrigger braces 140 and swung inwardly about the pivots 145 into an overlapped position as indicated in dotted lines in FIG- URE 5. After all the horizontal braces 144 and 147 have been disconnected from the outrigger braces 149, the latter may be swung inwardly about the pivots 142 to lie alongside the members 52. The general principles of operation and advantages of such outrigger braces are somewhat more fully set forth in my co-pending application, Serial No. ll,027, for Combination Outrigger and Front Leg Extension, filed February 25, 1960, to which reference may be had for a further understanding of the same. However, in general, the working loads on the front legs 40 and braces 140 are transmitted to jacks 14?, which, in turn, are supported by pads 150.

As shown in FIGURES 1, 2 and 3, at the lower end of the mast 34, the rear leg 42 is bent toward the front 7 legs 40 and terminates centrally between the latter. The

bent portion of the rear leg 42 is indicated by reference numeral 152 and at its lowermost portion, it is rigidly secured in any suitable manner to a transverse tube 154 secured at its outer ends to the bottom ends of the front legs 40 and held in place by means of diagonal brackets 156. Mounted in the frame formed by the brackets 156 is a pulley or sheave 158 and a similar sheave 160 is mounted on the transverse tube 154 approximately midway between the bottom ends of the front legs 40. A pair of sheaves 162 is mounted on an arm 164 pivotally mounted at 166 on the frame for-med by brackets 156, the function of the sheaves 158, 160 and 162 being more fully explained in the description of the operation of the device as set forth below.

Referring to FIGURE 2 of the drawing, the mast 34 is shown in full lines in the position which it occupies during normal road transport. As shown, the member 54 is fully extended against the stop 64, the racking plat form is folded forwardly to provide minimum overall height, and the top mast section 46 is pivoted downwardly, the weight of the forward portion of the mast being carried by the supporting structure 32. In this road transport position, the lifting leg or A frame 68 occupies the reduced central portion within the drums of the draw works 28 and, in view of the reduced number of diagonal braces provided, the vision of the driver of the truck in a forward direction is not unduly impaired. It will be particularly noted that, in the full line position illustrated in FIGURE 2, the mast extends rearwardly or overhangs the truck body by a rather considerable amount as compared to the overhang at the front although, in each case, the amount thereof is well within the allowable limits of the various State laws governing road transport.

After the truck has been backed into position near the selected well site, the first step to be taken is to raise the upper mast section 46 from its full line position to its dotted line position in FIGURE 2. This is accomplished by taking a strain upon the line 98 which extends over pulley 192 to the cathead 104 of the draw works which produces a toggle action of the pivoted members 8082, causing the latter to straighten out to a point where they may be held in place by means of the latch 106. This action is also illustrated in FIGURES 8 and 9 and, after the upper mast section 46 has been extended to the position shown in FIGURE 8 and the latch 106 actuated, the line 93 may be disconnected from the cathead 104 and disregarded until it is desired subsequently to prepare the rig once again for road transport.

With the upper mast section 46 extended to the dotted line position as shown in FIGURE 2, the regular fast line 126 from the draw works 28 is passed over the pulley 162 and thence forwardly to the fast line sheave 116 of the crown block assembly and thence, in the known manner around the travelling block and cross sheave of the crown block to the dead line sheave 118, the opposite pulley 162 and back to the draw works 28. A single line 168 is connected from the book of the travelling block 128 around the sheaves and 158 and is securely attached to a suitable fitting at the outer end of the lifting leg or A frame 68. Operation of the draw works will now cause the hinge support including the members 52 and 54 to be pivoted upwardly about the pivot-s 5'8 and 60, the main hinges 66 being raised above the truck body as the members 54 contract. When the members 54 are fully contracted and the parts in the position as indicated in FIGURE 3, further operation of the draw works causes the lifting leg 68 to raise the mast 34 about the main hinges 66, the roller 76 at the end of the lifting leg 68 sliding along the rear mast leg 42. When the mast 34 has been fully elevated to the position as shown in FIG- URE l, the automatic latch operates to retain the parts in the positions shown. The reverse operation of lowermg the mast may be accomplished by following the above described steps in reverse order, the air cylinder 38 being employed to initiate the downward movement.

It will be apparent that, by reason of the structure herelndescribed, it is possible to utilize a relatively high mast while at the same time complying'with theState laws regulating road transport. Furthermore, by utiliz ing the moving. hinges 66, I am able to secure a large effective lever arm or movement for the efi'icicnt utilization of the lifting leg 68, both the raising of the hinges and the lifting of the mast being accomplished in a continuous operation by actuation of the draw Works.

i It will be apparent that numerous other modifications, alterations, and deviations from the specific structures which have been shown and described herein solely for the purposeof illustration of a preferred embodiment will occur to one skilled in the art without departing from the spirit and scope of the invention as set forth in the following claims. i

I claim: I

1. A truck-mounted well servicing rig comprising a pair of main hinge supports at opposite sides of the truck body adjacent the rear thereof each having two members pivotally connected together at their outer ends and pivotally connected at their inner ends to spaced points sectionhaving two front legs and a single rear leg, main hinges pivotally connectingtthe'lower ends of each of said front legs to'the respective hinge supports, an A framepivotally mounted onthe truck bodyand'havinga roller on the truck body, at least one 'offsaid members com-v prising a pair oftelescopically arranged sections and limit stops providing limited extensibility, a mast of generally triangular cross-section having two front-legs and a single rear leg interconnected by spaced girts, main hinges pivot-Q ally connectingthe lower 'ends of each of said front legs to the respective hinge'supports, an A frame pivotally mounted at its'base onthetruck body and having, guides and a roller at its outer end-engageable'with said rear leg .for raising andlowering said mast, latch means at'the outer end of said A frame for releaseably connecting the latterto said rear leg when said mast is in fully raised, over-center position; a draw works on said truck body, a crown block assembly and travelling block on said mast, fast and dead lines interconnecting said draw works, said crown block assembly and said travelling block, and means including a plurality of sheaves rotatably mounted at the lower end of said mastand a raising line extending from said travelling block oversa'id sheaves to the outer end of said A frame whereby operation of said draw at its outer end, engageablewith said rear legfor raising and lowering said mast, a draw works on said truck body,

a crown block assembly and travelling block on said mast, fast and deadlines interconnecting said draw works, said crown block Lassembly and 1 said travelling block, and

'means including aplurality of sheaves rotatably mounted atthe lower en-d ofsaid mast and a raising line extending from said=-travelling block ov'er said sheaves to the outer end of said Aframewhereby operation of said draw works first retracts the extensible sections of said members to elevate said main hinges and thereafter causesysaid A frame toraisesaid mast; into operating position, said A frame serving to support the rear leg of the 'mast in its upright operating position.

4. A truck-mounted well servicing rig comprising a pairjof main hinge supports each having two members pivotally connected together at their outer ends and pivotally connected 'at their inner ends to spaced points lines interconnecting saiddraw works, said crown block assembly and 'said. travelling, block, and means" including a plurality of shea'vesJrotatably mounted at the lower end of said mast and a raising line extending from said travelling block over'said sheaves to the outer, end

I of said lifting leg whereby operation of said draw works works first retracts theextensible section of said members V to elevate said main hinges and thereafter causes said A frame to raise said mast into operating position.

2. A truck-mounted well servicing rig comprising 'a,

pair of main hinge supports at opposite sides of the truck body adjacent the. rear thereof each havingtwo members pivotally connected together at their outer ends and pivotally connected at their inner ends to spaced points on the truck body, at least one of said members comprising a pair of telescopically arranged sections and limit stops providing limited extensibility, a mast of generally triangular cross-section having twofront legs and a single rear leg interconnected by spaced girts, main hinges pivot ally connecting the lower ends of each of said front legs to the respective hinge supports, .an A frame pivotally fmounted at its base on the truck body and having guides and a roller at its outer end engageableiwith said rear leg for raising and lowering said mast, adraw works on said truck body, a crown block assembly and travelling block on said mast, fast and deadlines interconnectingfsaiddraw first retracts the extensiblesections of said members to elevate said main hinges and'thereaftertcauses said lifting'legto raise said mast into operating position said lifting leg serving to supporttherear leg of the mast in its upright operating position. I

In a truck-mounted well servicing rig, a pair of main hinge supports pivotally connected t o said truck body,'a mast having atleast two front legs and a singlejrear leg,

main hinges'fpivotally connecting the lower ends of each 7 of said front legs tovthe respectivehinge supports, a lifting leg-pivotally mounted on said truck body and having'its outer end slidably engageablewith a track on said rear leg for raising and lowering said mast, a draw works on said truck body, a crown block as'sembly and travelling block on said mast, fast and dead lines interconnecting said draw works, said crown block assembly and said travelling block, and means including a plurality of sheaves rotatably mounted at the lower end of said mast and a raising line extending from saiditravelling block over said sheaves f to the'outer end of said'lifting leg whereby operation of I said draw works firstcauses said main hinge supports to works, said crown block assembly andsaid travelling block, and means including a plurality of sheaves rotatably mounted at thelower end of said mast and a raising.

line extending from said travelling block over said sheaves to the outer end of-said A frame whereby operationof said draw works first retracts the extensible Sections of said members to' elevate said main hinges andtherea fter causes said A position.

3. A truck-mounted well servicing rig comprising a a pair of main hinge supports each having two members pivotally connected together at their outer ends and pivotally connected at their innerends to spaced points on the 'truckbody, at least one of said members comprising extensible sections, a mast pf generally,triangularecrossframe to raise said mast into operating pivot thereby elevating said mainhingesand thereafter causes said lifting leg to raise said mast about said main hingessaid liftingleg serving to support the rear leg of the mastinits upright operating position.

References Gted by the Examiner- UNITED STATES PATENTS 2,583,958 1/52 Moon l89l1 2,664,976 1/54 Woolslayer et ah; 189-11 2,673,629 3/54 Woolslayer et a1. 189-15 2,703,634 3/55 Lee 189 11 2,742,260 1 4/5 6 Patterson.

JACOB L. NACKENOFF, Primary Examiner. i

WILLIAM I. MUSHAKE, c. ANGEL, JOELREZ- 'NEK, RICHARD -w. ,DETT, Examiners.-

COOKE, BENJAMIN BEN- 

1. A TRUCK-MOUNTED WELL SERVICING RIG COMPRISING A PAIR OF MAIN HINGE SUPPORTS AT OPPOSITE SIDES OF THE TRUCK BODY ADJACENT THE REAR THEREOF EACH HAVING TWO MEMBERS PIVOTALLY CONNECTED TOGETHER AT THEIR OUTER ENDS AND PIVOTALLY CONNECTED AT THEIR INNER ENDS TO SPACED POINTS ON THE TRUCK BODY, AT LEAST ONE OF SAID MEMBERS COMPRISING A PAIR OF TELESCOPICALLY ARRANGED SECTIONS AND LIMIT STOPS PROVIDING LIMITED EXTENSIBILITY, A MAST OF GENERALLY TRIANGULAR CROSS-SECTION HAVING TWO FRONT LEGS AND A SINGLE REAR LEG INTERCONNECTED BY SPACED GIRTS, MAIN HINGES PIVOTALLY CONNECTING THE LOWER ENDS OF EACH OF SAID FRONT LEGS TO THE RESPECTIVE HINGE SUPPORTS, AN A FRAME PIVOTALLY MOUNTED AT ITS BASE ON THE TRUCK BODY AND HAVING GUIDES AND A ROLLER AT ITS OUTER END ENGAGEABLE WITH SAID REAR LEG FOR RAISING AND LOWERING SAID MAST, LATCH MEANS AT THE OUTER END OF SAID A FRAME FOR RELEASABLY CONNECTING THE 